Chem 334 - Fall 1998 - Organic Chemistry I
Portland State University - Dr. Carl C. Wamser


Chapter 3 Notes: Acid-Base Reactions

Bronsted-Lowry Acid/Base

Acidity Constant (Ka)

usually simplified to
HA <==> H+ + A-

Acid Strength (pKa)

pH and pKa

Structural Effects on Acid Strength

Acid-Base Reactions

CH3COOH + OH- <==> CH3COO- + H2O
acid (pKa = 5) + base <==> base + acid (pKa = 15.7)
reaction favored for stronger acid

reaction favored to the right

Acid-Base Reactions

CH3COOH + H2O <==> CH3COO- + H3O+
acid (pKa = 5) + base <==> base + acid (pKa = 1.7)
reaction favored to the left


Acid-Base Reactions

HC=CH + Na+NH2- <==> HC=C-Na+ + NH3
acid (pKa = 25) + base <==> base + acid (pKa = 35)
reaction favored to the right

Acid-Base Reactions

CH3OH + CN- <==> CH3O- + HCN
acid (pKa = 16) + base <==> base + acid (pKa = 9)
reaction favored to the left

Lewis Acids

H+ + H2O <==> H3O+
L acid + L base <==> new O-H bond


BF3 + NH3 <==> F3B-NH3
L acid + L base <==> new B-N bond